How efficient is the immigration service at Oakland?

You can look up historical immigration wait times for any U.S. airport at the CBP web site.

From a quick look, it appears that average wait times at OAK vary dramatically, from as little as a few minutes to over an hour, with no obvious (to me) pattern. But it appears that most international arrivals at OAK are much later in the evening, so you may get lucky with a 5 pm arrival.

OAK doesn't have Automated Passport Control kiosks, though Global Entry is available if you are in that program.

I have come into OAK on the Norwegian Air flight from Oslo (not the one from Stockholm) and we were in line (i.e., queue) over 35 minutes. US Citizens. About one-third the way back the cabin. The experience had us thinking very strongly of paying for Global Entry.

The examination at itself took two minutes, only because we still had a European apple to discard.

FWIW: When I arrived at OAK on Feb 1st 2016 on the Norwegian flight from Stockholm my seat was about 2/3 the way back. There was a single combined queue for all passengers except those with Global Entry. Only 2 of the 5 CBP booths were staffed. It took 55 minutes to get through and there were still probably 150 people behind me.

We went through Oakland Airport in the autumn of 2014 on the Norwegian airlines flight from Oslo. Clearly they were not setup for international travel - I hope things have improved now.

We were near the back of the plane (787) and there was just one long queue. We were American citizens and it took almost 2 hours to get through the line!! This was around 6 pm local time but in the wee hours of the morning Oslo time. Lots of Norwegian families with kids in line. An absurd wait and a shocking face for America compared to how efficient most European entry points are.

Make sure you go to the bathroom on the plane, as there are no bathrooms before the immigration inspection.

OAK, Norwegian out of Gatwick. Row 35. US citizens. It's been 40 minutes so far, probably another 10 to go. They've got APC kiosks going but it doesn't look like they save any time at all. There IS a bathroom back of the room. Posting while waiting in line, after googling for info on the kiosks.

The experience was comically BAD for a single plane to be processed. It appears that they are not prepared to handle a full Norwegian Dreamliner. There is poor signage to divide US citizens vs other, the roped lanes led us away from the automated kiosks so someone had to re-rope the lanes. One of the customs agents was having a bad day and began yelling at passengers, and in the meantime, because it was so slow, the luggage was stacked four high on the conveyor and was actually backing up into the belt. Then another agents takes a second look at the kiosk picture and the baggage goes through a tiny X-ray machine .. it all led to big queues and lots of frustration ... OAK not ready for prime time.